Adapter assembly for an anesthetic equipment

ABSTRACT

A keyed filling system for delivery of a liquid anesthetic agent from an anesthetic vessel to a receiving container of an anesthetic agent delivery equipment is disclosed. The system comprises at least one movable unit that allows a relative movement of said anesthetic vessel in relation to said anesthetic agent delivery equipment when said anesthetic vessel is arranged at said anesthetic agent delivery equipment for discharging said liquid anesthetic agent into said receiving container of said anesthetic agent delivery equipment. The movable unit may be provided on an adapter for being arranged on a bottle comprising an anesthetic agent and for insertion into a filling assembly of an anesthetic agent delivery equipment, or at a filling equipment into which a bottle or adapter is insertable for filling the anesthetic delivery equipment with liquid anesthetic agent. In this manner for instance leakage of anesthetic agent and wear of the adapter is avoided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a system comprising an adapter assembly for connecting a vessel, such as a bottle, containing a liquid anesthetic agent to anesthetic equipment devised for delivery of the anesthetic agent from the vessel to the equipment via the adapter. More particularly, the present invention relates to such an adapter assembly having improved leakage safety.

2. Description of the Prior Art

An anesthetic vaporizer for use during medical treatment comprises usually a vessel for receiving liquid anesthetic agent, and is connected to a system for delivering the vaporized anesthetic agent from the anesthetic vaporizer to the lungs of a patient. For this purpose, the vessel is filled with the liquid anesthetic agent before starting the medical treatment. Moreover, the vessel may needs to be replenished with further liquid anesthetic agent during the medical treatment. The anesthetic agent is supplied in liquid form in an anesthetic bottle, facilitating transport and storage of the anesthetic agent. When filling the vessel of the anesthetic vaporizer, the anesthetic liquid has to be conveyed from the interior of the anesthetic bottle to the interior of the vessel in the anesthetic vaporizer.

Typical anesthetic agents are known as Halothane, Isoflurane, Enflurane, Sevoflurane, and Desflurane. In order to ensure that only the correct anesthetic agent is filled into an anesthetic vaporizer that is dedicated to a specific single anesthetic agent, keying systems are known. For instance U.S. Pat. No. 6,585,016 or WO 2005/056093 disclose keyed anesthetic vaporizer filling systems for facilitating the delivery of a liquid anesthetic agent from an anesthetic bottle to an anesthetic vaporizer. Such keyed anesthetic vaporizer filling systems usually include a bottle adapter to be arranged on the anesthetic bottle, having a keying system, wherein a mating keying system is provided on the anesthetic vaporizer.

When the bottle with the adapter is to be arranged in the filling assembly, the bottle may be grasped and directed towards the filling assembly. The bottle is arranged with the key system of the bottle adapter in line with the key system in the filling assembly. Then, the adapter is pushed into the filling assembly. However, often the key system does not mate initially, as the user may not position the two keying systems in exact register. Then the bottle and the adapter have to be rotated at least slightly in order for the key systems to mate. During such rotation and manipulation of the bottle with the adapter it may happen that the sealed screw connection between the bottle and the adapter may become loose due to a torque transmission between the bottle and the adapter, especially if the bottle is moved in a direction opposite the fastening direction of a thread of the adapter or bottle during such manipulation. There may also exist a possibility that the adapter will jam during the insertion, which might lead to a torque transmission induced leakage, depending on the human factor, e.g. during handling of the adapter by healthcare personnel.

Furthermore, the adapter may unscrew from the bottle when locked to the filling system of the vaporizer. For instance, during filling, the bottle may unintentionally, at least partly, be unscrewed from the adapter, as healthcare personnel may be distracted from this task. Thus, the seal between the bottle and the adapter may become compromised and anesthetic agent may be released to the atmosphere, which should be avoided of understandable reasons.

In US2007/034284A1 a filling system for anesthetic evaporators, dealing with this issue is disclosed. The filling system comprises an anesthetic-specific code portion provided on a filler neck such that a filler keying code thereof has design corresponding to an anesthetic agent specific keying code on an adapter neck of a bottle adapter. A hinge is provided between the adapter neck and a threaded sleeve of the bottle adapter allowing for a hinged relative movement between the adapter neck and a threaded sleeve of the bottle adapter. The bottle adapter is thus divided into two segments in longitudinal direction thereof.

The hinge solution comprising the two segment bottle adapter is of rather complicated design rendering manufacture of the adapter burdensome. For instance, the hinge comprises a sealing O-ring that needs to be assembled. Moreover, this sealing O-ring may wear mechanically over time. As liquid anesthetic agents usually are of aggressive nature, this wear is accelerated as the sealing O-ring comes into contact with the anesthetic agent. This may lead to a leakage in the bottle adapter, when the adapter is mounted on the anesthetic bottle, and such anesthetic bottle is mounted to an anesthetic vaporizer, which is disadvantageous. It is desired to prevent leakage of an anesthetic agent to the surrounding environment of several reasons, amongst others related to patient safety and user safety.

Hence, an improved keyed system comprising an adapter having improved leakage safety would be advantageous, and in particular a keyed system, adapter, and/or anesthetic vaporizer filling system, e.g. allowing for increased flexibility, user friendliness, and/or patient safety.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing an adapter and a method of operating an adapter according to the appended patent claims.

According to an aspect of the invention, a keyed adapter assembly is provided. The keyed adapter is provided for arrangement on an anesthetic vessel devised for containing a liquid anesthetic agent at a first end portion of the adapter, and for arrangement at a filling assembly of an anesthetic agent delivery equipment at a second end portion of the adapter. The first end portion of the adapter comprises a movable unit in form of a cylindrical portion that is rotatably arranged in relation to body of the adapter. In an embodiment, the adapter comprises at least one keying protrusion arranged on the adapter for mating with a corresponding at least one recess of said filling assembly, wherein said protrusions are arranged on said cylindrical portion at the second end. The cylindrical portion is rotatably arranged on said adapter. Thus, the first and second end portion may have a fixed relation to each other, while providing rotatability of the adapter assembly in an advantageous manner.

In an embodiment, the cylindrical portion may be arranged in an area with reduced diameter of the adapter, wherein the cylindrical portion may comprise protrusions dimensioned to abut the area with reduced diameter of the adapter in order to form a frictional engagement. In some embodiments, the portion said with reduced diameter of said adapter body comprises the plurality of external friction protrusions dimensioned to abut said cylindrical portion internally. The protruding height of each of the protrusions may be dimensioned for providing a desired frictional engagement. The protrusions may be in the form of ridges, bulges, burls, semispheres, or have a conical, frustoconical, or pin shape, or similar projecting shapes. At least three protrusions, e.g. ridges may be provided. The cylindrical portion may comprise an extension portion extending to the end of the adapter. Moreover, the cylindrical portion may comprise a bevel for making it easier to assemble the cylindrical portion.

In another embodiment the cylindrical portion may be provided with a spring rotationally biasing the cylindrical portion to a home position.

Further embodiments of the invention are defined in the dependent claims, wherein features for the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

Some embodiments of the invention provide for leakage prevention when filling an anesthetic vaporizer from an anesthetic bottle via an adapter.

Some embodiments provide for reduced wear of the adapter.

Some embodiments provide for a continuous channel for flow of a liquid anesthetic agent through the adapter.

Some embodiments provide for an adapter having at least one keying element movable relative the adapter.

It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, features and advantages of which embodiments of the invention are capable of will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

FIG. 1 is a cross-sectional view of a bottle adapter according to an embodiment of the present invention;

FIG. 2 is a perspective view of an embodiment of a bottle adapter;

FIG. 3 is an exploded view of the adapter of FIG. 2;

FIG. 4 is a view from above of the assembled adapter of FIG. 2;

FIG. 5 is a cross sectional view of the adapter of FIG. 2, taken along the line B B of FIG. 4;

FIG. 6 is a cross sectional view of the adapter taken along the line A-A of FIG. 4;

FIG. 7 is an enlarged view of section C of FIG. 6;

FIG. 8 is a view from above of an embodiment of a cylindrical part of a bottle adapter;

FIG. 9 is a cross sectional view of the cylindrical part of FIG. 8, taken along the line A-A of FIG. 8;

FIG. 10 is an enlarged cross sectional view of section C of FIG. 8 illustrating a wall section of the cylindrical part of FIG. 8;

FIG. 11 is an enlarged cross sectional view of section B of FIG. 8 illustrating an end portion of the cylindrical part of FIG. 8;

FIG. 12 is an enlarged cross sectional view illustrating an end portion of the assembled bottle adapter of FIG. 2;

FIG. 13 is a cross-sectional view similar to FIG. 12 of another embodiment; and

FIG. 14 is a side view of the embodiment according to FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific embodiments of the invention now will be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements.

According to embodiments, a keyed filling system for delivery of a liquid anesthetic agent from an anesthetic vessel to a receiving container of an anesthetic agent delivery equipment is provided.

The system comprises at least one movable unit that allows a relative movement of said anesthetic vessel in relation to said anesthetic agent delivery equipment when said anesthetic vessel is arranged at said anesthetic agent delivery equipment for discharging said liquid anesthetic agent into said receiving container of said anesthetic agent delivery equipment. The movable unit may be arranged in a bottle adapter and/or a filling assembly of an anesthetic vaporizer. Embodiments will be elucidated further below.

FIG. 1 shows an adapter 20 having a first end portion 40 comprising a collar 31 having one or more keying slits 32 for mating cooperation with protrusions on an anesthetic bottle (not shown). Moreover, the collar comprises internal threads 33. Alternatively, or in addition to threads 33 other means for arrangement may be provided in other embodiments. For instance friction fit, a bayonet socket, a click lock type, a locking lever engageable with the bottle, etc. Thus, the adapter 20 can be placed on a bottle containing an anesthetic agent by removing a lid arranged on the bottle and screwing the adapter onto the bottle for replacing the lid, in a conventional manner. The adapter may include a valve system arranged in an intermediate portion 42 of the adapter. Such a valve system may comprise a valve body and a spring system including a spring and a retainer 39, see FIG. 3. At its outer surface, the adapter is provided with one or more protrusions 70 forming a key system together with one or more corresponding mating recesses in a filling assembly.

In order to mitigate the above-mentioned possibility of leakage and wear, in an embodiment, the adapter 20 is provided with a cylindrical portion 80, as for instance shown in FIG. 1. A cylindrical portion 80 comprises keying protrusions 70 at a second end portion 41. When assembled on adapter 20, the cylindrical portion 80 is arranged in a portion 81 of the adapter having a reduced outer diameter. The cylindrical portion 80 is free to be rotated around the adapter body. In some embodiments the cylindrical portion 80 may alternatively or in addition be pivotable in relation to a longitudinal axis 90 of the adapter 20.

Provided the cylindrical rotatable portion 80, the operation of the adapter of FIG. 1 is as follows. The adapter 20 is brought into contact with a filling assembly. Firstly, a front 91 portion of the adapter 20 without radially extending protrusions 70, is inserted into an upper inner of a cylindrical body of the filling assembly (not shown). Such a filling assembly having a cylindrical body 54 is for instance described in U.S. Pat. No. 6,585,016, which hereby is incorporated by reference in its entirety for all purposes.

However, if the key system, notably the protrusions 70 and the recesses in the adapter 20 and the filling assembly do not mate initially, the user may rotate the cylindrical portion 80 until the protrusions 70 register with the recesses in the filling assembly. The adapter 20 is thus provided with at least one keying element 71 that is movable relative to an adapter body 22 of the adapter 20. Thus a continuous channel for flow of a liquid anesthetic agent through the adapter 20 is provided. Moreover, the adapter body 22 is made of one monolithic piece of material, and the issue of wear induced leakage is dealt with.

In case sufficient rotational resistance is provided between the cylindrical portion 80 and the portion with reduced diameter 81, this operation is made by moving the bottle in the rotational direction, around the longitudinal axis 90, or in any other direction suitable for achieving this purpose. In this case, the cylindrical body 81 rotates in a defined manner together with the adapter 20 and the bottle attached thereto. Alternatively, the cylindrical body 80 may be rotated manually in relation to a substantially fixed adapter 20 in order to bring the protrusions 70 in register with corresponding recesses in the filling assembly.

When the protrusions 70 are arranged in line with the recesses in the filling assembly, the adapter is free to be further pushed into the filling assembly. Thus, the embodiment according to FIG. 1 is operational for remedying the issue of torque transmission induced leakage mentioned above.

Embodiments of the bottle adapter 20 is shown more detailed and in different views in FIGS. 2 to 14, wherein the same reference numerals are used for like elements as with reference to the previous Figures.

FIG. 3 is an exploded perspective view of the adapter 20 of FIG. 2, wherein the cylindrical portion 80 with protrusions 70 is shown disassembled from the above mentioned adapter body 22 at the second end portion 41 of the adapter 20. The valve assembly 21 is provided in portion 42 of the adapter 20.

FIG. 4 is a view from above of the assembled adapter of FIG. 2, seen in the direction of the first end portion 40.

FIG. 5 is a cross sectional view of the adapter 20 of FIG. 2, taken along the line B-B of FIG. 4, wherein the cylindrical portion 80 is removed and the portion 81 with reduced diameter of adapter 20 is clearly shown.

FIG. 6 is a cross sectional view of the adapter 20 taken along the line A-A of FIG. 4.

FIG. 7 is an enlarged cross-sectional view of section C of the adapter 20, as shown in FIG. 6.

The cylindrical portion 80 is shown in more detail in FIG. 9. The rim of a first end 88 of the cylindrical portion 80 may be provided with a bevel 82 in order to more easily assemble the cylindrical portion onto the adapter body by sliding the latter with the first end 88 over the second end portion 41 of the adapter 20. FIG. 8 is a view from above of the cylindrical part 80 of bottle adapter 20 or bottle adapter 20, wherein the cylindrical part 80 is shown in FIG. 9 in a cross sectional view taken along the line A-A of FIG. 8.

Furthermore, the inner surface 89 of the cylindrical body 80 may be provided with one or several protrusions, e.g. ridges 83. In the present embodiment the cylindrical body 80 is provided with three ridges 83, being shown in FIG. 8, separated by angle of 120 degrees from each other around the circumference of the inner surface 89. By having arranged the ridges 83 distributed along the circumference of the inner surface 89 of the cylindrical portion 80, an even rotation is obtained avoiding jamming of the cylindrical portion 80 and thus providing a well defined distribution and fit of the cylindrical portion on the adapter 20.

Alternatively or additionally to ridges, the protrusions may be in the form of bulges, burls, semispheres, or have a conical, frustoconical, or pin shape, or similar projecting shapes.

The ridges 83 have a defined length extension in longitudinal direction and a height from the inner surface 89 of the cylindrical portion 80, as shown in FIG. 9 and FIG. 10. Thus, ridges 83 are provided such that they contact the outer surface of the adapter portion 81 with reduced diameter, in order to provide a well defined frictional force counteracting rotation of the cylindrical portion around the adapter portion 81 with reduced diameter. The length of the ridges 83 is also adjusted so that a predetermined desired frictional force is obtained. In FIG. 9, the ridges 83 are shown extending over half of the length of the cylindrical portion 80. The frictional force that is adjusted by means of the ridges 83 defines that the cylindrical portion 80 is advantageously rotatable in relation to the adapter portion 81 with reduced diameter.

The frictional force counteracting rotation of the adapter is to be chosen such that it is lower than a force at which the bottle is unscrewed from thread 33. This ensures that the adapter does not rotate too loosely, but risk for leakage of anesthetic agent is avoided, as unintentional unscrewing of the bottle from the adapter is avoided. The bottle may be screwed onto adapter 20 and unscrewed therefrom by holding the adapter with one hand and twisting the bottle with an other hand.

Alternatively or additionally such protrusions may also analogously be provided on the exterior of the lower portion of the cylindrical portion 81 of the adapter body 22 in some embodiments.

The lower portion of the cylindrical portion 80 may be extended as shown in FIG. 9 so that it reaches all the way to the bottom end of the adapter 20, as is shown in further detail in the enlarged FIG. 11, which shows the encircled area B of FIG. 9. In this embodiment, the cylindrical portion 80 extends all the way to the bottom face of the adapter body by an extension portion 84. In the embodiment of FIG. 1, this extension portion 84 is not present.

The cylindrical portion 80 is shown to surround a portion of the lower portion of the adapter. However, the cylindrical portion could have a smaller or larger extent, such as all the way up to the slits 32 of the adapter.

The cylindrical portion 80 may be provided with a rotational return element, such as a spring, which urges the cylindrical portion 80 to a home position. Such a home position may be marked by a detent so that it may be sensed when moving the cylindrical portion 80 in rotational direction.

The frictional engagement may additionally or alternatively be provided by a contact area between the upper and/or lower rim of the cylindrical portion 80 and a portion of the adapter positioned opposite thereto. As shown in FIG. 13, the cylindrical portion is provided with one or several ribs 85 having an extension in the radial direction. These ribs abut the adapter as shown in order to form a frictional engagement.

Alternatively, the ribs, or similar friction protrusion elements, may be arranged equivalently on the adapter body arranged adjacent said cylindrical portion (not shown). For instance, friction protrusion elements may be arranged on the outer surface of the adapter portion 81 with reduced diameter. In this case the inner surface of the cylindrical portion mating the protrusions may be cylindrical without protrusions in order to provide a rotational movement.

Alternatively, or in addition, both mating elements may be provided with protrusions, allowing for a limited rotational movement over an angular range defined by ribs engaging in rotational direction. Here, at least three protrusions are arranged on the adapter portion 81 or the cylindrical portion, and in addition at least one protrusion element is arranged on the corresponding other of the cylindrical portion or the adapter portion 81, respectively.

When having protrusions on both the cylindrical portion and the adapter portion 81, these may be arranged such that a rotational movement between these two is limited. In one case the protrusion elements are arranged to meet in rotational direction as stop elements, providing a rotational limited angular movement between two rotational end positions. The protrusions may be formed such that a rotational movement between the cylindrical portion and the adapter portion 81 is hindered, but not precluded, when the corresponding protrusions meet. In this manner, a tactile or audible feedback may be provided to the user, e.g. by a clicking sound when protrusions pass each other. This may be provided by the protrusions having different protruding height.

One or several of these ribs 83 can also perform an indexing function in order to define a home position of the cylindrical portion. FIG. 14 shows a web-like flexible member 86 extending down from the lower rim of the cylindrical member. The opposite edge of the adapter is provided with a detent 87 in which the flexible portion 86 may engage. When the cylindrical member is rotated, the flexible member is forced out of the detent 87 and forms a frictional engagement with the edge. When the cylindrical portion is returned to its starting position, the detent 87 forms an indication of a home position.

In addition, the cylindrical portion 80 may be provided with a plurality of detents 87 such that a rotation of the bottle in relation to the filling portion of a filling assembly (as for instance filling portion 52 described in U.S. Pat. No. 6,585,016) may be sensed by the user via a tactile or acoustic feedback provided by the flexible portions 86 engaging or disengaging with the detents 87.

The cylindrical portion may have any suitable shape conforming to the shape of the adapter portions positioned adjacent to the cylindrical portion. The cylindrical portion may have a freedom to be rotated in relation to the adapter, so as to adjust the protrusions arranged on the cylindrical portion in line with the recesses in the filling assembly.

Other keying systems than the described and illustrated may be arranged and used along with embodiments of the adapter.

The adapter may be made in a plastics material, such as nylon or PVC. The adapter may comprise colors that indicate which type of anesthetic agent the adapter is useable for.

In addition, locking elements may be provided to, at least temporary, lock such rotational elements and provide an adapter without rotational spin tolerance, if so desired.

A keyed filling system for delivery of a liquid anesthetic agent from an anesthetic vessel to a receiving container of an anesthetic agent delivery equipment, may thus be provided, wherein the system comprises an adapter of embodiments of the invention and a filling assembly in a anesthetic agent delivery equipment.

Alternatively to a bottle, other vessels suitable for containing liquid anesthetic liquids may be provided in embodiments.

Keying elements may also be provided in other forms, such a protrusions in a filling assembly and recesses in a bottle adapter.

The improved adapter of embodiments of the invention may be used on anesthetic filling systems of the prior art, such as the filling systems described in WO 2005/056093 or U.S. Pat. No. 6,585,016, which are incorporated herein by reference in their entirety for all purposes.

Further modifications may occur to a skilled person reading this specification and such modifications are intended to be included within the scope of the present invention as defined in the appended patent claims.

Although the present invention has been described above with reference to specific embodiment, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims and other embodiments than those described above are equally possible within the scope of the appended claims. 

1. A keyed adapter assembly comprising: an adapter body configured for arrangement on an anesthetic vessel at a first end portion of said adapter, said anesthetic vessel containing a liquid anesthetic agent, and configured for arrangement at a filling assembly of an anesthetic agent delivery equipment at a second end portion of said adapter, said second end portion of said adapter comprises a movable unit that is rotatably arranged in relation to said adapter body, wherein said movable unit comprising a movable cylindrical portion coaxially arranged around said adapter body of said adapter at said second end portion.
 2. The keyed adapter assembly according to claim 1, comprising at least one external keying protrusion on said adapter that mates with a corresponding recess of said filling assembly, said at least one keying protrusion being arranged externally on said movable cylindrical portion.
 3. The keyed adapter assembly according to claim 1, wherein said movable cylindrical portion is frictionally engaged for retention with said second end portion of said adapter.
 4. The keyed adapter assembly according to claim 3, wherein said cylindrical portion is arranged at a portion with reduced diameter of said adapter body, and wherein said cylindrical portion comprises a plurality of internal friction protrusions dimensioned to abut said portion with reduced diameter of said adapter body that frictionally retain said movable cylindrical portion in engagement with said adapter body.
 5. The keyed adapter assembly according to claim 4, wherein each of said friction protrusions has a length and a height dimensioned for frictional engagement of said cylindrical portion with said portion with reduced diameter of said adapter body.
 6. The keyed adapter assembly according to claim 4, wherein said friction protrusions are ridges, and wherein said cylindrical portion comprises at least three of said ridges.
 7. The keyed adapter assembly according to claim 3, wherein said cylindrical portion is arranged at a portion with reduced diameter of said adapter body, and wherein said portion with reduced diameter of said adapter body comprises a plurality of external friction protrusions dimensioned to abut said cylindrical portion internally that frictionally retains said movable cylindrical portion in engagement with said adapter body.
 8. The keyed adapter assembly according to claim 7, wherein each of said friction protrusions has a length and a height dimensioned for frictional engagement of said cylindrical portion with said portion with reduced diameter of said adapter body.
 9. The keyed adapter assembly according to claim 7 wherein said friction protrusions are ridges, and wherein said portion with reduced diameter of said adapter body comprises at least three of said ridges.
 10. The keyed adapter assembly according to claim 1, wherein said cylindrical portion comprises an extension portion extending to an end of said second end portion of said adapter.
 11. The keyed adapter assembly according to claim 1, wherein a first end of said cylindrical portion comprises a bevel.
 12. The keyed adapter assembly according to claim 1, wherein said cylindrical portion is provided with a biasing unit that is arranged to rotationally bias said cylindrical portion to a home position.
 13. The keyed adapter assembly according to claim 1, wherein a home position of said cylindrical portion is provided by a detent that is provided for tactile sensing when moving said cylindrical portion in rotational direction.
 14. The keyed adapter assembly according to claim 13, wherein said cylindrical portion comprises a plurality of internal friction protrusions dimensioned to abut said portion with reduced diameter of said adapter body for a frictional engagement of said cylindrical portion with said adapter body, wherein at least one of said internal friction protrusions defines said home position.
 15. The keyed adapter assembly according to claim 1, comprising a contact area between an upper and/or lower rim of said cylindrical portion and a portion of said adapter body positioned opposite thereto to provide a frictional engagement between said cylindrical portion and said second portion of said adapter.
 16. The keyed adapter assembly according to claim 1, comprising a web-like flexible member extending downwardly from a lower rim of the cylindrical member, wherein an opposite edge of said adapter body carries a detent in which the flexible portion engages to indicate a home position, and wherein, upon rotation of said cylindrical member, said flexible member is forced out of said detent and provides a frictional engagement with said edge.
 17. The keyed adapter assembly according to claim 1, wherein said cylindrical portion comprise a plurality of detents that, upon rotation of said anesthetic vessel in relation to said filling assembly, produce a tactile or acoustic feedback by engaging or disengaging said detents.
 18. The keyed adapter assembly according to claim 1, wherein said adapter body is formed as a single monolithic piece of material. 